# cache_set

Set a value in the optional Redis companion cache

Agent View of the PolicyLayer registry record for `cache_set`. HTML page: https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-set

## Facts

- Tool: `cache_set`
- Server: Project Guardian MCP (`1999azzar/project-guardian-mcp-server`) — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server.md
- Homepage: https://github.com/1999AZZAR/project-guardian-mcp-server
- Risk category: Write (Medium risk)
- Registry record: grade F, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "cache_set",
    "arguments": {}
  }
}
```

## Why cache_set is rated Medium

cache_set performs a write operation that creates or modifies data in a Redis cache. This is reversible (values can be overwritten or deleted via cache_delete) and has limited blast radius—misuse would affect only cached data, not persistent project state or critical systems. The 'optional' nature of the Redis companion suggests it augments rather than controls core functionality.

From the tool's own definition: "Tool description states 'Set a value in the optional Redis companion cache', which is a write operation that creates or modifies cached data."

## Use case

AI agents use cache_set to create or update resources in Project Guardian MCP, usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Project Guardian MCP environment.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Project Guardian MCP:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "cache_set": {
      "limits": [
        {
          "counter": "cache_set_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Project Guardian MCP (37)

- `cache_delete` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-delete.md
- `delete_data` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-data.md
- `delete_entity` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-entity.md
- `delete_observation` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-observation.md
- `delete_relation` — Destructive — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/delete-relation.md
- `close_ui` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/close-ui.md
- `execute_sql` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/execute-sql.md
- `initialize_memory` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/initialize-memory.md
- `scan_container_image` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/scan-container-image.md
- `start_ui` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/start-ui.md
- `stop_ui` — Execute — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/stop-ui.md
- `analyze_git_changes` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/analyze-git-changes.md
- `cache_get` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-get.md
- `cache_scan` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/cache-scan.md
- `export_data` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/export-data.md
- `get_file_context` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-file-context.md
- `get_project_guidance` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-project-guidance.md
- `get_session_context` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-session-context.md
- `get_timeline` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/get-timeline.md
- `inspect_untrusted_text` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/inspect-untrusted-text.md
- `list_harness_stores` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/list-harness-stores.md
- `open_node` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/open-node.md
- `query_data` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/query-data.md
- `read_graph` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/read-graph.md
- `read_graph_stream` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/read-graph-stream.md
- `scan_project_secrets` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/scan-project-secrets.md
- `search_nodes` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/search-nodes.md
- `sync_central_memory` — Read — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/sync-central-memory.md
- `add_observation` — Write — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/add-observation.md
- `create_entity` — Write — https://policylayer.com/tools/1999azzar-project-guardian-mcp-server/create-entity.md
- …and 7 more: https://policylayer.com/tools/1999azzar-project-guardian-mcp-server.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=1999azzar-project-guardian-mcp-server · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/1999azzar-project-guardian-mcp-server